Took long enough, maybe it's tired

[Jean]

Just turned 20k miles on it since I've had it (almost trouble free miles) and here is the first issue.

Symptoms.

Starts right up, idles ok so I don't think it's ignition related?
After about a minute or so it starts to die, but won't on the first try. When driving it feels like car lost half of it's power, and giving it more gas does not result in acceleration. Started today, there were no indication earlier this morning, so this happened just about an hour ago on my lunch break.

Checked all the hoses under the hood (pretty much all of them have been replaced with new, including intake boot not too long ago). Unplugged and plugged back in 3 relays on the drivers side, the maf, checked spark plug wires on the spark plugs and the distributor just in case as well.

The fuel filter has been replaced about 20k miles ago, now the fuel pump has not. The idle control valve and idle control valve module were also replaced to see if they would help lower my idle, so I do have a spare of each.

Car starts right up, cluster works fine, but it stumbles to a point where I didn't feel comfortable driving it on the public road and parked it.

So, ECU or Fuel Pump?

[george graves]

O2 sensor? Just throwing it out there.

[Autobahn Sport]

M10?

[Jean]

I will check the o2 sensor connection (I've had the o2 sensor come off the exhaust /header last year and I could still drive the car, it was pretty loud but this feels completely different).

Yes, m10b18.

[Mless5]

Replace fuel filter with a straight hoses to test. Clean the pick up net on the pump. Might be FPR too.

[TDE30]

Give it a try, it got rid of my brother's power loss issues with his M30.

[Jean]

Seafoam won't do anything in this case, I've used seafoam before and it barely made any difference. This engine is beyond cleaning, it needs to be replaced soon, but for now I just need it to run like it did this morning w/o any stumble.

I will check the fuel pump net under the back seat, I can also replace the inline pump on the drivers side near the fuel tank, I also do have a spare set of injectors with new o-rings and fpr that I was saving for when I put a new engine in...

[cferb]

Definitely check the fuel pump, could also be FPR.

It sounds like the same symptoms I was having when my FPR was on backwards(It was adjustable, and it was on the way the instructions said...) Also sounds like it could be a bad vacuum leak, or AFM related, but I guess you checked the AFM already.

[OrganicMechanic]

I say FP.

[gazellebeigem3]

if its not the fuel pump, replace the main and fuel pump relays. I do more relays on e30s than pumps.

[M42Technik]

Definitely sounds like the fuel pump, had the same problem.

[golde30]

yeah, i had problem like this on my 325is, it was the fuel pump.

[daniel]

sounds like my car before i replaced the fuel pump.

[Dave]

gas cap on tight?

[Jean]

Limped it home. Checked the basics again, each cylinder is firing, battery/voltage is good before and after igniton. Each injector is firing as I can feel them ticking by pressing a screwdriver at the body of each one.

Replaced a vacuum line going from the fpr to the intake manifold as it was the last hose I haven't replaced, and it started right up and idled even better. Thinking that was that I let the car idle and it slowly died again.

Pulled the back seat and removed the fuel pump cover to inspect the fuel pump / pickup only to find out that one of the two fuel pump hoses have a pressed on clamps on them, so I left that alone until tomorrow.

When I pulled the fuel pump relay it dies just like it does on the road at idle...

Don't think it's the ICV, as it stubles even at high rpm with the voltage disconnected from the ICV.

Looked under the passenger rear, moved the inline fuel pump vibration damper a little and it or the fuel pump made some noises...

I'll replace the inline pump on saturday and see what happens. All hoses are ok, nothing is disconnect or loose. I guess it could still be a AFM and I'll test it's resistance by opening the flap. Hopefully it won't be an ECU as I don't have a spare..

Car has a sweet spot between 2k-4k rpm, anything less and it stumbles, anything more and it bogs. Had to drive it home with left foot braking, to keep the idle up.